B Chromosomes Have a Functional Effect on Female Sex Determination in Lake Victoria Cichlid Fishes

• DOI: 10.1371/journal.pgen.1002203
• Publication Date: 2011-08-18T18:59:14Z
• Authors: Kohta Yoshida; Yohey Terai; Shinji Mizoiri; Mitsuto Aibara; Hidenori Nishihara; Masakatsu Watanabe; Asato Kuroiwa; Hirohisa Hirai; Yuriko Hirai; Yoichi Matsuda; Norihiro Okada
• Keywords: Cichlid; B chromosome; Genetic algorithm; Sex linkage

The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of sex-determination may also play role speciation, little is known about cichlids. To understand these fish, we performed cytogenetic analysis 11 species from Victoria. B chromosomes, which present addition to standard were found at high prevalence rate (85%) In one species, chromosomes female-specific. Cross-breeding using females with and without demonstrated that presence leads female-biased sex ratio this species. believed be selfish genetic elements effect on phenotype lack protein-coding genes, study provides evidence have functional female determination. FISH BAC clone containing chromosome DNA suggested derived chromosomes. Determination nucleotide sequences (104.5 kb) revealed several genes chromosome, suggesting potential contain genes. Because some amphibians arthropods thought cichlids represent an evolutionary transition toward generation